The specific aims of this proposal are: 1) to produce monoclonal antibodies to the Old World species of leishmania (i.e. L. donovani and L. tropica) to be used to develop clinical assays for distinguishing between these species of leishmania at the primary lesions; 2) to produce monoclonal antibodies to be used to dissect and analyze the leishmantia antigenically (using both the insect form (promastigote) and intracellular (amastigote) forms of the parasite; 3) isolate and purify these antigens by biochemical or molecular cloning techniques to study their effectiveness in producing "protective immunity" in vivo model systems. The major objective of these studies is to ellucidate the antigens and mechanisms relevant to establishing "protective" immunity to leishmaniasis which should lead to the eventual production of a vaccine to Leishmaniasis.